Apparatus for drying wood



- 3 Sheets-Shet J F. HOPE ETAL.

APPARIIUS FOR DRYING WOOD Fned July 19, 1926 ///zezr APPARATUS FOR DRYING iwooD Filed July 19, 1926 s sheets-sheet 2 M7/lass: V

"sbpta 18, 192s. 4 1,684,627

J.- F. HOPE E1' AL APPARATUS FOR DRYNG Filed July 19, 192e 1 s sneetsneet 3 f Zw l ATTORNEYS.4

Patented` Sept. 18, 1928i.

UNITED ysmrias P ArsN'r orifice.. f

JOHN mHoPnANnJoHN r.' Horn, on kansas CITY., MIssoURIQ A'arremrrns ron ngaYrNs Woon.Y

' Application led July 19, 1926. Serial No. 123,273.

This vinvention relates to wood drying kilns, and more especially to kilns of that type wherein a vacuous condition is established and sustained for effecting a uniform curingof the' stock without case-hardening its surface, as stock hardened at its surface too rapidly is not fullycured at its center and Will .split or check in a reiatively short time. Kilns operating under a vacuum, as l0 exemplified by Patent No. 1,353,591, issued September 21, 1920, perform the curing function efliciently, but we have found that the time required in-the operation of curing by such afkilncan be materially shortened by providing -a front endof greater-air inlet capacity relative to the ycross-sectional arca of the body portion, and a large obstructing heating coil or radiator, whichheats the 1ndrawn air and at the same time so retards it that, if unobstructed otherwise, a vacuous condition is` created and established back of the coil or radiator. As a result a high teinperature is attained which, in conjunction lwith the vacuous condition, greatly facilitates the drying or curing operation, it being` obvious that loaded trucks Within the kiln and obstructing circulation, materially lincrease or intensify the vacuous condition mentioned. `As a result of the provision of an inlet opening of 'materially greater cross sectional area than the body portion and of the use of a correspondingly enlarged heater, the process of curing is greatly enhanced and the output of the'kiln materially increased. y

Our primary objecttherefore is to produce a kiln for curing stock as elliciently .but with muchgreater celerity than the kiln of said patent, and a further object is lto provide a kiln-having doors which can be 'opened easily by oneman, and vwhich has otherfeatures which generally .facilitate the operation of moving the trucks ata .small expenditure of power and cost.- f l With these objectsinpview the invention consists in eert'ainnovel and useful features of construction and vcombinations of parts as hereinafter described and claimed;V and'in order that it may be fullyunderstood, reference is to be had to theaccompanying drawings, in which '55 III-1I of Figure 1.

Figure 1 is a side elevation, partlyy broken I Figure 3 is lan enlarged vert-ical section throughV the body of the kiln, on the line IIIHIII of Figure 2.

y Figure 41 is a vertical transverse sectionV on the line IV-IV of Figure 1.`.

Figure 5 is an enlarged fragmentary side elevation to clearly disclose the mechanism for impartingV travel .to the Wood drying trucks when wlthinthe kiln. `r`

Figure 6 1s yan enlarged side elevation ofk a stop for arresting forward travel of the truc/lis when they attain their finalposition in the kiln, the stop A'being shown in reversed positionfrom that in which it appearsv in Figurejl.'

Figure 7 isa plan View of the stop asit appears in Figure 6.' I g Referringto the draw`ngsin detail, 1indicates a li-lnstruct-ure Ycapable of .accominodating simultaneously a numbery of trucks containing stacked slabs orsticlrs of wood to be dried, ,the liln v'being of considerable length and preferably of rectangularform in cross section. At its front end-it is venlarged as at 2 by an increase inheightor otherwise, andsubstantially filling the enlargement or the front end thereof is a heating device, such asl a system of steam coils, a-s at .3., f t its. opposite endthe Vkilnfis equipped with. one or more `suction fans t of anyy preferred or conventional. type whereby) a circulationfof air'may be established, theA air drawn into the front of t-he kilnfbeing heated gthroughcontact with the heating coils -andlexhaustcd at .the fan end of the casing, the obstruction of lbeing preferably arranged lto operate edgewise, movingupwardto luncover and downward to cover said opening. 'A similar door opening 7 nearithe front end `of the structure iscontrolled'by a similar door 8.- As thefans arevoperating Vcontinuously .there 4,is a sucvovercome by manual power where. slide doors soY .tional pull on the doors which can be readily are employed, and-for this reasonslide doors are preferable to hinged doors.V Running vinto way composed of plates 9, and-said Vplates are connected by a longitudinal trackwayfcom- Vthe kiln from the doorvopening 5 'is a trackground level so as not to interfere with the` doors. Extending longitudinally of and centrally between the trackwayplates 10, is a slotted guideway composedof parallel rails 12 divergingat their rea-r ends at 13 to provide a fiaring mouth for the slotted guideway, the said rails 12 being secured to anchor blocks or plates 14. i

Forward of the trackway 9 and `adjacent thereto, is a transverse trench 15, enlarged as at 16' and 17 Within the kiln, and extending through said trench and suitably journaled therein is a shaft 19 vequipped within the trench openings 16 and 17, with grooved pulleys 20, and fastened theretoat the front endsl are chains or cables21 equipped at their rear ends with hooks 22. A lever 23 is journaled upon the shaft 19 within opening 18, and is preferably forked at its lower end at 24 to conveniently carry the gravity pawl 25 for engagement with a ratchet wheel 26 keyed or otherwise secured upon the shaft 19.

A slotted guideway 27 leads throughopening 5 andis disposed between the outer ends of the' plates of trackway 9 midway between the latter, and in line with the rearmost side of Vsaidslotted guideway 27 are guide rails 28, 29, the ends of said guideways nearest opening 5, being inclined as at 30 in the same direction. Said guideways 28 and 29 are within the kiln structure, and also withinA the latter and adjacent the opposite wall thereof from that provided with the door openings, is a bumper 31. In line with the slotted longitudinal guideway hereinbefore described and forward of the trackway 11, is a stop device consisting of a base plate 32 having an upstanding lug 33 at its rear end and a notched upstandin lug 34 near its front end, the front wall of t e notch of said lug constituting a shoulder 35. pivotally linked together at 38, the rear end of bar 36 being pivoted to lug 33 and having a toe 39 to engage the base 32 and arrest the swinging movement of `said link when it has attained a'vertical position. VThe bar 37 atv its free or front end, is adapted to engage the notch of lug 34 when bar 36 is vertical, and

brace the latter against reverse or downward swinging movement sothat it shall constitute an abutment or stop. For convenience in operating this stop device, afoot plate `or lever 40 is provided with a narrow shank 41 fitting in the bifurcation at the front or free endV of bar 37. y The" operator by applying pressure on this foot plate or lever fulcrumed on lug 34, can readily. trip the-brace bar 37 from enga ement withthe notched plate so that the linilgied bars may fall to the collapsed or inoperative positionvindicated by full lines, Fig-V ure 6.

Bars 36 and 37 arey Trucks v42 of conventional design and adapted to carry loads of stacked lumber in slab or stick form, are provided with casters 43, to run on the trackways, and each truck has a depending guide pin 44, to engage the guideways and center the'trucks on the trackways, and the kiln is so proportioned with respect to said trucks that when loaded trucks are standing on trackways 9 and 11, the space between said trucks will accommodate a number of other trucks of the same type with the adjacent sides of allV the trucks' abutting. Y

In the practical operation of the kiln, the door 6 is operated to permita truck loaded Vwith greenstock, to be run into the kiln on and after leaving thekiln closes door 6, andn the heated air circulating Vthrough the kiln carries off a certain amount of moisture from the load on the truck. After the-wood has been subjected to this treatment for a suffi- Vcient length of time, an operator through the instrumentality of lever 23, draws theV truck forward until the entrance opening 5 is unobstructed. The operator. then trips the pawl in the direction lindicated by the` adj a- .I

cent arrow, Figure 5, and another operator enters the kiln anddisengages the chains from-the first named truck. Another loaded truck is then run into the kiln `through the door opening 5, andthe operator within theA kiln or entering for-the purpose, draws the chains or cables back and hooks themtoy the rear side of the last-named truck. y He leaves the kiln and the door is closed, and after a sufficient length of time has elapsed for furthercuring of the Wood on the first truck and initial curing of the wood on the last truck, the lever -is again operated to drawl the, rearmost truck forward and hence push the other truck ahead of ituntil the door opening 5 is again left unobstructed. The pawl is i again trippedv from. engagement with Vthe ratchet wheel, thedoor again opened, and

another loaded truck run into thevkiln and engaged by the hooks. The `o `rations previously described are repeate and are-repeated again and again until the truck'first placed 'in the kiln has `attained a position in line with the door opening 7 ,at which time it is 'clamped against the stop device.A By the time the first truck has reached the stop device, the Wood thereon has been largely cured. Y

and after sufficient time has elapsed for its the condition and character of the wood and by proper inspection,the door 8 is opened V complete curing,-this being determined by and an operator enters the kiln through said door opening 7 and trips the stop'device so that the truck containing the cured wood can be withdrawn from the kiln through the opening 7. He then resets the stop device, leaves the kiln and recloses the door 8. The lever is then manipulated to advance all of the trucks until the second one has .reached the stop device, and then another truck containing green or uncured wood'is placed in the kiln through the door opening 5. lt has been found by maintaining a certain degree of heat within reasonable limits and a proper suctional pull or circulation, that by the time a truck has progresse/l intermittently in the manner explained from the rear to the 'iront end ot the kiln, its contents have been largely cured, it being obvious that the condition or kind or character ol the wood, the degree ci heat and suctional force all aiiect the period required for curing operation. lt is important that the front end of the' kiln shall be of such size in excess ot the cross sectional area of the body ot the kiln that the current ot' air passing through the kiln would travel at a substantial increase'oit speed alter it leaves the enlarged end if it were not for the fact that the heatingl coils so obstruct said enlarged end that the operation oli the fans maintains a va-cuous condition within the body of the kiln back o'l its enlarged end, the

loaded trucks of course further obstructingl the circulation and therefore increasing the vacuous condition. lt has been Jfound in practice that wood can be cured eiiiciently and in a minimum period of time by a kiln ot the character described, and that the appliances enable two men to handle the trucks and 'the like with celerity and economy.

From the above description it will be ap*l parent that while we have. described and claimed the preferred embodiment of the 1nvention, it is to be understood that we reserve the right to make all changes properly talling within the spirit and scope o'l the ap pended claims.

Y l/Ve claim:

l. A wood drying kiln open at its iront and rear ends and provided near its ends with side openings, the liront ond of the kiln being et greater cross-sectional area than the `body signatures.

of greater cross-sectional area than the body portion, edgewise movable doors controlling the side openings of the kiln, one or moresuction lans to exert suction rearwardly through the kiln through the front and rear ends', a heating device in the enlarged front end to retard the passage of air drawn into the liront end by the sectional action; to a suilicient degree to insure the production of a vvacuous condition in the kiln back of said heating device when the doors are closed.

3. ln a wood drying kiln, a tunnel portion having side door openings near its ends, par allel tracks on the bottom of the tunnel portion and extending longitudinally therein, parallel pairs oi tracks extending through the door openings and intersecting the irstnamed tracks, a slotted guideway extending longitudinally of the tunnel between longitudinal tracl s thereof and the said pairs of transverse tracks, said slotted guideway havf ing a flaring mouth at one end, wheeled trucks to run on said tracks and provided with depending pins to operate within the slotted guideway when the trucks are moving longitudinally within the tunnel for the greater part of the length thereof between the transverse tracks, slidable doors normally closing the side openings of the tunnel, suction means Jfor drawing vair into one end oit' thetunnel and exhausting it at the other end, and means within the entrance end of the tunnel for heating the air entering the tunnel.

ln witness whereof we hereunto ailix our JOHN r. Horn. JOHN T. Horn. 

